This invention relates generally to an improved bit retainer for impact type pneumatic tools or the like. More specifically, this invention relates to an improved bit retainer for releasably retaining bits having an elliptical flange thereon in power tools or the like that positively prevents accidental discharge of the bit from the tool.
The bit retainer of this invention is an improvement over a latch-type quick release retainer that has been manufactured and used for a number of years. The latch-type retainer includes an oval bore for receiving the bits with oval flanges and has portions of the bore misaligned thus necessitating a quarter-turn of the bit for insertion and removal. To prevent accidental removal or discharge of the bit, a cam or latch member extends transversely of the bore between the misaligned portions. The latch member is retained by a spring which biases the latch member inwardly, blocking a portion of the bore.
The arrangement is generally effective, except that a twisting motion applied in such a way to cause relative movement between the bit and the tool, can cam the latch member out of the bore and inadvertently release the bit. It is an object of this invention to provide a bit retainer that is easily operable to insert and remove bits and, yet, one that positively prevents the inadvertent release or discharge of the bit.